Update 4.2.1 release notes

Author: michaelklishin

release-notes/4.2.1.md

@@ -43,6 +43,15 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
    GitHub issue: [#14852](https://github.com/rabbitmq/rabbitmq-server/issues/14852)
 
 
+### Grafana Dashboards
+
+#### Enhancements
+
+ * The [dashboards](https://grafana.com/orgs/rabbitmq) were updated for RabbitMQ `4.2.x`.
+
+   GitHub issue: [#14849](https://github.com/rabbitmq/rabbitmq-server/pull/14849)
+
+
 ### Management Plugin
 
 #### Enhancements
@@ -65,6 +74,10 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
    GitHub issue: [#14872](https://github.com/rabbitmq/rabbitmq-server/pull/14872)
 
+ * AMQP 1.0 shovels ignored the `sasl` URI parameter.
+
+   GitHub issue: [#14867](https://github.com/rabbitmq/rabbitmq-server/pull/14867)
+
 
 ### OAuth 2 Plugin